ILX Lightwave LDT-5525 User Manual page 60

The LDT-5525 Temperature Controller uses i to determine the nominal temperature, T
is in °C.
-where T
n
The temperature, T , which is displayed by the LDT-5525 Temperature Controller is first calibrated as follows:
d
-where C1 and C2 are the constants stored by the user in the LDT-5525 Temperature Controller for the AD590.
The AD590 measurement is calibrated, at the factory, with C2 = 1 and C1 = 0 (nominal values). The AD590 grades of
tolerance vary, but typically this means that without adjusting C1 or C2, the temperature accuracy is +1 °C over its
rated operating range. If C1 and C2 are also calibrated, the temperature accuracy is +0.2 °C over its rated operating
range. However, the AD590 is not perfectly linear, and even with C1 accurately known there is a non-linear absolute
temperature error associated with the device. This non-linearity is shown in Figure C.1, reprinted from Analog
Devices specifications, where the error associated with C1 is assumed to be zero.
T = ( i / ( 1uA / K ) ) - 273.15
n
T = C1 + ( C2 * T )
d n
C-2
, by the formula:
n